Quote:
Originally Posted by Veeger
Nice one Rick...and that's billion with a "b". Very impressive how a guy in his backyard can image such a distant object!
-V
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First a correction. I see I got my eyes crossed looking up the redshift of the quasar. It's really only 8 billion light years away light travel time. I don't quite understand how I made that mistake.
Quote:
Originally Posted by Veeger
Amateur astrophotography has progressed to a remarkable degree.
-V
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You can say that again! When I built my first scope in 1954 the Hale 200" scope was only 5 years old and was taking amazing photos. Yet today many amateurs are taking better ones with "back yard" telescopes. Somehow, back then, man walking on the moon didn't seem all that unreasonable to me, but the idea I could take images that were in some ways as good or better than the Hale scope was taking at that time did seem beyond reason. Also the idea that I could have a computer far better than Univac at my disposal let alone have many of them in my house (even my microwave oven and cell phone have better computers than Univac) was also beyond belief.
As to the distance to a an object with a redshift of over 1 like this quasar, things get complicated. You have three distances. The common one is the light travel distance but the object was really much closer than that distance when the light was emitted. It's the expansion of the universe that causes the problem. Even though the object was much closer, say about 5.4 billion light years, the light had to travel 2.6 billion light years further to reach us because the space between us was expanding the whole time. Then you have its "current" distance. That would be about 11.5 billion light years if my math is right (and I'm lousy at this relativistic math). So we are seeing it as it existed some 8 billion years ago when it was 5.4 billion light years from us and if we could see it as it is today it would be over 11.5 billion light years away and the light would take several tens of billions of years to reach us as the expansion is a lot worse today than it was in the past. But since there are no quasars in our near by universe we may be save to assume that in the 8 billion years since that light left the quasar all have ceased to be quasars and are simply AGNs of one type or another.
Rick